Power steering pump and water pump assembly

ABSTRACT

A power steering pump and water pump assembly is disclosed. The assembly includes a power steering pump with a rotating shaft and a water pump. The water pump has a housing and a rotatable shaft for driving an impeller, which is mounted on an inner end of the shaft. An outer end of the water pump shaft engages the shaft of the power steering pump, and the power steering pump shaft drives the water pump shaft. The water pump may include a seal and a bearing having an inner race and outer race for supporting an outer end of the water pump shaft and cantilevering the shaft to support and journal the impeller. The shaft of the power steering pump may engage the shaft of the water pump through engagement of male and female torque transmitting profiles that axially slide together.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/426,335 filed Dec. 22, 2010, the disclosure of which is hereby incorporated by reference in its entirety.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

1. Field of the Invention

The present invention relates to power steering pumps and water pumps used in automobiles. More specifically, the invention relates to a power steering pump and water pump assembly.

2. Background Prior Art

In-line water pump and power steering pump assemblies are common in current automobile design and may be used in other applications as well. These assemblies may have the shaft of the power steering pump drive the shaft for the water pump. For example, one such design may be seen in U.S. Pat. No. 6,852,193.

When a leak or other issue develops in either the power steering pump or the water pump that requires the pump to be replaced, the pumps must be separated before the defective pump may be replaced. Separating the two pumps, however, may involve removing several components of the water pump before being able to separate the water pump from the power steering pump. As an example, the water pump housing may need to be disassembled and the impeller for the water pump may need to be removed from the shaft of the water pump. After completing those steps, the shaft of the water pump may be disengaged from the shaft of the power steering pump such that the two pumps may be separated. However, if the power steering pump is the pump being replaced, the operator must still reassemble the previously mentioned components of the water pump when replacing the assembly. These steps increase the labor and time required to replace a defective pump from the assembly of the water pump and power steering pump.

Consequently, a need exists for a power steering pump and water pump assembly that allows for a quicker disassembly, yet still allows the shaft of the power steering pump to drive the shaft of the water pump.

SUMMARY OF THE INVENTION

In one form, the invention provides for a power steering pump and water pump assembly. The assembly includes a power steering pump having a rotatable shaft extending from the power steering pump. The assembly also includes a water pump having a housing and a rotatable shaft for driving an impeller of the water pump. The shaft of the water pump is driven by the shaft of the power steering pump and an impeller is mounted on an inner end of the shaft of the water pump. The shaft of the water pump extends from the inner end to an outer end. The outer end of the water pump shaft is engaged by an end of the power steering pump shaft. The outer end of the water pump shaft is supported by a bearing having an outer race that is fixed to the housing of the water pump. The shaft of the water pump is cantilevered by the bearing to support and journal the impeller. The water pump also includes a seal between the bearing and the impeller.

In another form, the invention provides for a power steering pump and water pump assembly that includes a power steering pump having a rotatable shaft extending from the power steering pump. The assembly also includes a water pump having a housing and a rotatable shaft for driving an impeller of the water pump. The water pump shaft is driven by the shaft of the power steering pump and mounts the impeller at an inner end of the shaft. The water pump shaft extends from the inner end to an outer end, the outer end being engaged by an end of the power steering pump shaft by the interaction of a male torque transmitting profile and a female torque transmitting profile. At least one of the power steering pump shaft or the outer end of the water pump shaft includes the male torque transmitting profile and the other of the at least one of the rotatable shaft or the outer end of the water pump shaft includes the female torque transmitting profile. The male and female torque transmitting profiles axially slide together.

In yet another form, the invention provides for a water pump having a shaft adapted to be driven by another shaft that includes a torque transmitting profile. The water pump includes a housing defining a pumping chamber. An impeller is mounted on an inner end of the shaft of the water pump in the pumping chamber. The water pump also includes a bearing having an outer race that is fixed to the housing of the water pump and a seal between the bearing and the impeller. The water pump shaft extends from an inner end to an outer end, the outer end being engaged by an end of another shaft and supported by the bearing. The water pump shaft is cantilevered by the bearing to support and journal the impeller.

Additionally, in another form the invention provides for a method for disassembling a power steering pump and water pump assembly. The method includes providing an assembly which includes a power steering pump having a housing and a rotatable shaft extending from the power steering pump and a water pump having a housing and a rotatable shaft for driving an impeller of the water pump. The water pump shaft is driven by the shaft of the power steering pump. The shaft of the water pump mounts the impeller at an inner end of the shaft and the shaft extends from the inner end to an outer end, the outer end being engaged by an end of the power steering pump shaft by the interaction of a male torque transmitting profile and a female torque transmitting profile. At least one of the power steering pump shaft or the outer end of the water pump shaft includes the male torque transmitting profile and the other of the at least one of the rotatable shaft or the outer end of the water pump shaft includes the female torque transmitting profile. The power steering pump housing and the water pump housing are assembled with at least two fasteners. The method also includes removing the fasteners and axially sliding one of the power steering pump housing or the water pump housing away from the other of the power steering pump housing or the water pump housing.

One advantage of the invention is that the power steering pump and water pump assembly is configured such that the two pumps may be separated from the assembly by the removal of a few fasteners. Because the shaft of the power steering pump engages the shaft of the water pump in a male/female relationship that allows for the male/female components to axially slide together, the two pumps may be easily separated without having to disassemble several components of one of the pumps.

Another advantage of the invention is that the water pump may include a bearing to support and cantilever the water pump shaft such that less deflection occurs on an inner end of the water pump shaft where the impeller is mounted.

The foregoing and other objects and advantages of the invention will appear from the following description. In this description, reference is made to the accompanying drawings which form a part hereof and in which there is shown by way of illustration a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a power steering pump and water pump assembly embodying the invention showing one fastener used for connecting the power steering pump housing to the water pump housing;

FIG. 2 is an exploded view of the assembly of FIG. 1;

FIG. 3 is a cross-sectional view taken along line 3-3 from FIG. 1; and

FIG. 4 is a cross-sectional view taken along line 4-4 from FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-4, a power steering pump and water pump assembly 10 is shown. The assembly 10 includes a power steering pump 12 and a water pump 14. The power steering pump 12 includes a housing 16 and the water pump 14 has a housing 18 as well. The power steering pump 12 housing 16 is assembled to the water pump 14 housing 18 through fasteners 19 (only one shown in FIG. 1 for clarity). As shown in FIG. 2, the power steering pump 12 includes a rotatable shaft 13. The rotatable shaft 13 is driven by an engine (not shown) to pressurize and distribute power steering fluid as known to one skilled in the art. The power steering pump 12 shaft 13 drives the water pump 14.

As shown in FIG. 2, the water pump 14 housing 18 is constructed of a pair of mating housing parts 20, 22. The housing parts 20, 22 are fastened together with a series of fasteners 24. A gasket 26 is placed between the two mating housing parts 20, 22 to seal the connection of the two housing parts 20, 22 to prevent leaking coolant to the surrounding environment. The connection of the housing parts 20, 22 define a pumping chamber 28 for the coolant (as best shown in FIG. 3).

The water pump 14 includes an impeller 30 and a rotatable shaft 32 for distributing the coolant. The shaft 32 in the water pump 14 includes an inner end 34 disposed in the pumping chamber 28 and extends to an outer end 36. The impeller 30 is mounted on the inner end 34 of the rotatable shaft 32. This may be done by mounting the collar 38 on the inner end 34 of the rotatable shaft 32 of the water pump 14 and fitting the impeller 30 on the collar 38.

As shown in FIGS. 2 and 3, the water pump 14 also includes a bearing 40. The bearing 40 may be a double ball bearing that includes an outer race 42, an inner race 44, and balls 46. While a double ball bearing is preferable for the bearing 40, other types of bearings may be used including, but not limited to, needle bearings. The bearing 40 shown in FIG. 2 includes two seals 48 for keeping bearing lubricant in the bearing 40 and preventing contaminants from disrupting the proper functioning of the bearing 40. The outer race 42 of the bearing 40 is fixed relative to a part 20 of the water pump 14 housing 18. The inner race 44 of the bearing 40 is formed on an outer end 36 of the water pump 14 shaft 32. Although the inner race 44 and the shaft 32 are shown as an integral unit, it can be appreciated that the shaft 32 may be formed as a separate unit from the inner race 44, but be connected together, such as by a press fit.

The bearing 40 supports the outer end 36 of the shaft 32 of the water pump 14. Additionally, the shaft 32 is cantilevered by the bearing 40 to support and journal the impeller 30. Advantageously, this support of the impeller 30 by the bearing 40 may prevent excess deflection in the shaft 32 in the water pump 14 during the operation of the water pump 14 and rotation of the impeller 30. This may lead to better sealing properties of the water pump 14, resulting in less frequent refills of coolant, and longer life of the seal 46 of the water pump 14.

As mentioned above, the bearing 40 also includes a seal 46. The seal 46 is disposed between the impeller 30 and the bearing 40 to seal the coolant in the pumping chamber 28 from the bearing 40. As shown in FIG. 3, the seal 46 includes a mounting collar 48 that is fixed to housing part 20 and abuts a shoulder 50 of the shaft 32 in the water pump 14. The impeller 30 and mounting collar abut the seal 46.

The outer end 36 of the shaft 32 of the water pump 14 engages an end 52 of the rotating shaft 13 of the power steering pump 12. The engagement of the shafts 13, 32 occurs through an interaction of a male torque transmitting profile 54 and a female torque transmitting profile 56, with the profiles 54, 56 being engaged by axially sliding one into or over the other. As best shown in FIG. 4, the rotating shaft 13 of the power steering pump 12 forms the male torque transmitting profile 54 and the inner race 44 of the bearing 40 forms the female torque transmitting profile 56. Alternatively, the shaft 32 of the water pump 14 may form the female torque transmitting profile 56, such as in the circumstance where the inner race 44 of the bearing 40 is not formed integral with the shaft 32, but is formed as a separate component and press fit on the shaft 32. It can be appreciated that while the shaft 13 of the power steering pump 14 forms the male torque transferring profile 54 and the inner race 44 of the bearing 40 forms the female torque transferring profile 56 in the embodiment shown in FIGS. 1-4, the male/female orientation may be reversed between the water pump 14 and the power steering pump 12.

The torque transmitting profile 54, 56 is shown in FIGS. 2-4 as splines, however, other torque transmitting profiles that allow for a male and female profile to axially slide together are comprehended by the invention. Other torque transmitting profiles that would perform this function include, but are not limited to, hexagonal, double hexagonal, pentagonal, D-shaped, key, square, torx, torq-set, tri-wing, triple square, polydrive, pozidrive, phillips, one-way, slot drive, and bristol. As shown in FIGS. 2 and 3, the engagement between the male and female torque transmitting profiles 54, 56 may be protected with an o-ring 58 that is slid over the end 52 of the shaft 13 of the power steering pump 12. This o-ring 58 prevents any foreign particles from hindering the engagement of the male and female torque transmitting profiles 54, 56.

Because the torque transmitting profiles 54, 56 allow the shaft 13 of the power steering pump 12 to axially slide together with the inner race 44 of the bearing 40, assembly and disassembly of the power steering pump and water pump assembly 10 requires few steps. For example, one may disassemble the power steering pump 12 from the water pump 14 or vice versa by removing three fasteners 19 (only one fastener 19 shown in FIG. 1 for clarity) from threaded holes 60 (as shown in FIG. 2), which pass through the power steering pump 12 housing 16 and into part 20 of the water pump 14 housing 18. Once the fasteners 19 are removed, the water pump 14 and power steering pump 12 may be separated from each other by axially sliding one of the pumps 12, 14 away from the other. This method allows for efficient assembly and disassembly of the power steering pump 12 and water pump 14 assembly 10.

The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure. 

1. A power steering pump and water pump assembly comprising: a power steering pump having a rotatable shaft extending from the power steering pump; and a water pump having a housing and a rotatable shaft for driving an impeller of the water pump, the shaft being driven by the shaft of the power steering pump, the shaft of the water pump mounting the impeller at an inner end of the shaft and extending from the inner end to an outer end, the outer end being engaged by an end of the power steering pump shaft and supported by a bearing having an outer race that is fixed to the housing of the water pump, the shaft of the water pump being cantilevered by the bearing to support and journal the impeller, and further comprising a seal between the bearing and the impeller.
 2. The power steering pump and water pump assembly according to claim 1, wherein an inner race of the bearing is formed on an outer end of the water pump shaft.
 3. The power steering pump and water pump assembly according to claim 2, wherein the shaft of the power steering pump drives the shaft of the water pump by engagement of a male torque transmitting profile and a female torque transmitting profile, at least one of the power steering pump shaft or the inner race of the bearing includes the male torque transmitting profile and the other of the at least one of the rotatable shaft or the inner race of the bearing includes the female torque transmitting profile.
 4. The power steering pump and water pump assembly according to claim 3, wherein the male and female torque transmitting profiles are configured such that the male and female torque transmitting profiles may axially slide together.
 5. The power steering pump and water pump assembly according to claim 4, wherein the power steering pump shaft includes the male torque transmitting profile and the inner race includes the female torque transmitting profile.
 6. (canceled)
 7. The power steering pump and water pump assembly according to claim 1, wherein the bearing is a double ball bearing.
 8. The power steering pump and water pump assembly according to claim 1, wherein the power steering pump further includes a power steering pump housing and the power steering pump housing and water pump housing are assembled with at least two fasteners.
 9. A power steering pump and water pump assembly comprising: a power steering pump having a rotatable shaft extending from the power steering pump; and a water pump having a housing and a rotatable shaft for driving an impeller of the water pump, the shaft being driven by the shaft of the power steering pump, the shaft of the water pump mounting the impeller at an inner end of the shaft and extending from the inner end to an outer end, the outer end being engaged by an end of the power steering pump shaft by the interaction of a male torque transmitting profile and a female torque transmitting profile; wherein at least one of the power steering pump shaft or the outer end of the water pump shaft includes the male torque transmitting profile and the other of the at least one of the rotatable shaft or the outer end of the water pump shaft includes the female torque transmitting profile, and the male and female torque transmitting profiles axially slide together.
 10. The power steering pump and water pump assembly according to claim 9, wherein the power steering pump shaft includes the male torque transmitting profile and the outer end of the water pump shaft includes the female torque transmitting profile.
 11. The power steering pump and water pump assembly according to claim 9, wherein the torque transmitting profile is a profile selected from the group consisting of hexagonal, double hexagonal, D-shaped, key, pentagonal, square, torx, torq-set, tri-wing, triple square, polydrive, pozidrive, phillips, one-way, spline drive, slot drive, and bristol.
 12. The power steering pump and water pump assembly of claim 9, wherein the outer end of the water pump shaft is supported by a bearing having an outer race that is fixed to the housing of the water pump, the shaft of the water pump being cantilevered by the bearing to support and journal the impeller.
 13. The power steering pump and water pump assembly of claim 12, further comprising a seal between the bearing and the impeller.
 14. The power steering pump and water pump assembly of claim 12, wherein the bearing is a double ball bearing.
 15. The power steering pump and water pump assembly according to claim 9, wherein the power steering pump further includes a power steering pump housing and the power steering pump housing and water pump housing are assembled with at least two fasteners.
 16. A water pump having a shaft adapted to be driven by another shaft, the water pump comprising: a housing defining a pumping chamber; an impeller mounted on an inner end of the shaft of the water pump in the pumping chamber; a bearing having an outer race that is fixed to the housing of the water pump; and a seal between the bearing and the impeller; wherein the water pump shaft extends from an inner end to an outer end, the outer end being engaged by an end of the other shaft and supported by the bearing, and the water pump shaft is cantilevered by the bearing to support and journal the impeller.
 17. (canceled)
 18. The water pump according to claim 17, wherein the other shaft drives the shaft of the water pump by engagement of a male torque transmitting profile and a female torque transmitting profile, and at least one of the other shaft or the inner race of the bearing includes the male torque transmitting profile and the other of the at least one of the other shaft or the inner race of the bearing includes the female torque transmitting profile.
 19. The water pump according to claim 18, wherein the inner race of the bearing engages the other shaft by axially sliding the male and female torque transmitting profiles together.
 20. The water pump according to claim 19, wherein the inner race includes the female torque transmitting profile and the other shaft includes the male torque transmitting profile.
 21. (canceled)
 22. The water pump according to claim 16, wherein the bearing is a double ball bearing.
 23. A method for disassembling a power steering pump and water pump assembly, the method comprising: providing a power steering pump and water pump assembly which includes a power steering pump having a housing and a rotatable shaft extending from the power steering pump and a water pump having a housing and a rotatable shaft for driving an impeller of the water pump, the water pump shaft being driven by the shaft of the power steering pump, the shaft of the water pump mounting the impeller at an inner end of the shaft and extending from the inner end to an outer end, the outer end being engaged by an end of the power steering pump shaft by the interaction of a male torque transmitting profile and a female torque transmitting profile with at least one of the power steering pump shaft or the outer end of the water pump shaft includes the male torque transmitting profile and the other of the at least one of the rotatable shaft or the outer end of the water pump shaft includes the female torque transmitting profile, and the power steering pump housing and the water pump housing are assembled with at least two fasteners; removing the fasteners; and axially sliding one of the power steering pump housing or the water pump housing away from the other of the power steering pump housing or the water pump housing. 